Adhesive Wear

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Hendrik Van Brussel - One of the best experts on this subject based on the ideXlab platform.

Ramin Aghababaei - One of the best experts on this subject based on the ideXlab platform.

  • Micromechanical Origins of Adhesive Wear Mechanisms: From Asperity Smoothing to Debris Creation
    2020
    Co-Authors: Ramin Aghababaei, D H Warner, Jeanfrancois Molinari
    Abstract:

    The Adhesive Wear process consists of several physical phenomena including plasticity and fracture which occur at different length and time scales. Despite the critical importance of the Adhesive Wear process in all engineering applications, it is still described via classical, yet fully empirical, models [1,2] since the microscopic principles have not been yet understood. Using novel coarse-grained atomistic simulations , we for the first time capture the debris formation during the Adhesive collision between surface asperities [3]. A systematic set of atomistic simulations reveals a characteristic length scale that controls the Adhesive Wear mechanisms (i.e. asperity smoothing versus debris formation) at the asperity level. This length scale provides a critical Adhesive junction size where bigger junctions produce Wear debris by fracture while smaller ones smooth out plastically. This finding explains why Wear debris has not been observed in previous atomistic simulations of Adhesive Wear, where the junction is too small and/or weak to form debris by fracture. Based on this observation, we formulate a simple analytical model that predicts the transition in the asperity-level Adhesive Wear mechanisms in both the simulation results and atomic force microscope (AFM) Wear experiments. We show that the proposed framework opens up a new research path to implicitly model and explore the Wear process and revisit classical models. References: [1] J. F. Archard (1953) Journal of Applied Physics [2] E. Rabinowicz (1961) Journal of Applied Physics [3] R. Aghababaei, D.H. Warner and J.F. Molinari (2016) Nature Communications

  • Adhesive Wear law at the single asperity level
    Journal of The Mechanics and Physics of Solids, 2020
    Co-Authors: Kai Zhao, Ramin Aghababaei
    Abstract:

    Abstract Macroscopic Wear experiments in mid 1950s suggested an empirical Wear relation: Wear volume is linearly proportional to load and sliding distance. Recent asperity-level Wear experiments and simulations reported a breakdown of this law at the nanoscale, posing the fundamental question: Is the macroscopic Wear relation recoverable at the asperity level? Here we show that discrepant observations of Wear relations can be reconciled into a unified framework. Using systematic long-timescale coarse-grained molecular dynamic Wear simulations, we show that a linear Adhesive Wear law can be recovered at the single-asperity level only if the material removal is dominated by plastic deformation, confirming the longstanding Archard's theoretical hypothesis. Alternatively, the relation breaks down when cleavage fracture or thermally activated atomic detachment governs the loss of material at the asperity level.

  • on the origins of third body particle formation during Adhesive Wear
    Wear, 2019
    Co-Authors: Ramin Aghababaei
    Abstract:

    Abstract The process of material removal during Adhesive sliding contact (i.e. Adhesive Wear) remains one of the least understood areas in the field of tribology. The main reason for this limited understanding is that, direct observation and modeling of third body formation during Adhesive contact present notorious challenges [1] . Recent coarse-grained 2D atomistic simulations [2] revealed the existence of a critical junction size, with larger asperity junctions forming third-body Wear particles and smaller junctions smoothing plastically. In this study, we examine the critical junction size model in a three-dimensional configuration. We present a 3D coarse-grained model potential and large scale 3D simulations of third-body particle formation in an idealized single asperity contact. Our simulations validate the prediction of the critical junction size model [2] for the formation of third-body Wear particles. Directions for future studies on computer modeling of Wear processes are discussed.

  • emergence of self affine surfaces during Adhesive Wear
    Nature Communications, 2019
    Co-Authors: Enrico Milanese, Ramin Aghababaei, Tobias Brink, Jeanfrancois Molinari
    Abstract:

    Friction and Wear depend critically on surface roughness and its evolution with time. An accurate control of roughness is essential to the performance and durability of virtually all engineering applications. At geological scales, roughness along tectonic faults is intimately linked to stick-slip behaviour as experienced during earthquakes. While numerous experiments on natural, fractured, and frictional sliding surfaces have shown that roughness has self-affine fractal properties, much less is known about the mechanisms controlling the origins and the evolution of roughness. Here, by performing long-timescale molecular dynamics simulations and tracking the roughness evolution in time, we reveal that the emergence of self-affine surfaces is governed by the interplay between the ductile and brittle mechanisms of Adhesive Wear in three-body contact, and is independent of the initial state. Surface roughness evolution with time is key for tribological applications. Here, the authors demonstrate by numerical simulations the evolution of sliding surfaces into self-affine morphologies during Adhesive Wear due to the formation of a third body trapped at the interface.

  • Adhesive Wear mechanisms uncovered by atomistic simulations
    Friction, 2018
    Co-Authors: Jeanfrancois Molinari, Ramin Aghababaei, Tobias Brink, Lucas Frérot, Enrico Milanese
    Abstract:

    In this review, we discuss our recent advances in modeling Adhesive Wear mechanisms using coarse-grained atomistic simulations. In particular, we present how a model pair potential reveals the transition from ductile shearing of an asperity to the formation of a debris particle. This transition occurs at a critical junction size, which determines the particle size at its birth. Atomistic simulations also reveal that for nearby asperities, crack shielding mechanisms result in a Wear volume proportional to an effective area larger than the real contact area. As the density of microcontacts increases with load, we propose this crack shielding mechanism as a key to understand the transition from mild to severe Wear. We conclude with open questions and a road map to incorporate these findings in mesoscale continuum models. Because these mesoscale models allow an accurate statistical representation of rough surfaces, they provide a simple means to interpret classical phenomenological Wear models and Wear coefficients from physics-based principles.

D K Dwivedi - One of the best experts on this subject based on the ideXlab platform.

  • Adhesive Wear behaviour of cast aluminium silicon alloys overview
    Materials & Design, 2010
    Co-Authors: D K Dwivedi
    Abstract:

    Abstract This paper describes the various technological aspects related to Adhesive Wear of cast aluminium–silicon (Al–Si) alloys. Number of hypothesis and theories proposed in the last two decades in order to explain the different phenomenon related with Wear and friction, and influence of test parameters (such as load, sliding speed, counter-surface) and work material properties (like mechanical and metallurgical) on tribological behaviour of aluminium–silicon alloys have been presented and discussed.

  • Adhesive Wear behaviour of cast aluminium–silicon alloys: Overview
    Materials & Design, 2010
    Co-Authors: D K Dwivedi
    Abstract:

    Abstract This paper describes the various technological aspects related to Adhesive Wear of cast aluminium–silicon (Al–Si) alloys. Number of hypothesis and theories proposed in the last two decades in order to explain the different phenomenon related with Wear and friction, and influence of test parameters (such as load, sliding speed, counter-surface) and work material properties (like mechanical and metallurgical) on tribological behaviour of aluminium–silicon alloys have been presented and discussed.

Jeanfrancois Molinari - One of the best experts on this subject based on the ideXlab platform.

  • Micromechanical Origins of Adhesive Wear Mechanisms: From Asperity Smoothing to Debris Creation
    2020
    Co-Authors: Ramin Aghababaei, D H Warner, Jeanfrancois Molinari
    Abstract:

    The Adhesive Wear process consists of several physical phenomena including plasticity and fracture which occur at different length and time scales. Despite the critical importance of the Adhesive Wear process in all engineering applications, it is still described via classical, yet fully empirical, models [1,2] since the microscopic principles have not been yet understood. Using novel coarse-grained atomistic simulations , we for the first time capture the debris formation during the Adhesive collision between surface asperities [3]. A systematic set of atomistic simulations reveals a characteristic length scale that controls the Adhesive Wear mechanisms (i.e. asperity smoothing versus debris formation) at the asperity level. This length scale provides a critical Adhesive junction size where bigger junctions produce Wear debris by fracture while smaller ones smooth out plastically. This finding explains why Wear debris has not been observed in previous atomistic simulations of Adhesive Wear, where the junction is too small and/or weak to form debris by fracture. Based on this observation, we formulate a simple analytical model that predicts the transition in the asperity-level Adhesive Wear mechanisms in both the simulation results and atomic force microscope (AFM) Wear experiments. We show that the proposed framework opens up a new research path to implicitly model and explore the Wear process and revisit classical models. References: [1] J. F. Archard (1953) Journal of Applied Physics [2] E. Rabinowicz (1961) Journal of Applied Physics [3] R. Aghababaei, D.H. Warner and J.F. Molinari (2016) Nature Communications

  • Adhesive Wear and interaction of tangentially loaded micro contacts
    International Journal of Solids and Structures, 2020
    Co-Authors: Son Phamba, Tobias Brink, Jeanfrancois Molinari
    Abstract:

    Abstract Current engineering Wear models are often based on empirical parameters rather than built upon physical considerations. Here, we look for a physical description of Adhesive Wear at the microscale, at which the interaction between two surfaces comes down to the contact of asperities. Recent theoretical work has shown that there is a critical micro-contact size above which it becomes energetically favorable to form a Wear particle. We extend this model by taking into consideration the elastic interaction of multiple closely-spaced micro-contacts in 2D, with different sizes and separation distances. Fundamental contact mechanics solutions are used to evaluate the elastic energy stored by shearing the micro-contacts, and the stored energy is compared to the energy needed to detach a single joined debris particle or multiple debris particles under the micro-contacts. Molecular dynamics simulations are used to test the predictions of the outcome for various sets of parameters. Our model provides simple criteria to evaluate the energetic feasibility of the different Wear formation scenarios. Those criteria can be used to rationalize the transition between mild and severe Wear regimes and help define the notion of asperity.

  • Adhesive Wear and interaction of tangentially loaded micro contacts
    arXiv: Soft Condensed Matter, 2019
    Co-Authors: Son Phamba, Tobias Brink, Jeanfrancois Molinari
    Abstract:

    Current engineering Wear models are often based on empirical parameters rather than built upon physical considerations. Here, we look for a physical description of Adhesive Wear at the microscale, at which the interaction between two surfaces comes down to the contact of asperities. Recent theoretical work has shown that there is a critical micro-contact size above which it becomes energetically favorable to form a Wear particle. We extend this model by taking into consideration the elastic interaction of multiple nearby micro-contacts in 2D, with different sizes and separation distances. Fundamental contact mechanics solutions are used to evaluate the elastic energy stored by shearing the micro-contacts, and the stored energy is compared to the energy needed to detach a single joined debris particle or multiple debris particles under the micro-contacts. Molecular dynamics simulations are used to test the predictions of the outcome for various sets of parameters. Our model provides simple criteria to evaluate the energetic feasibility of the different Wear formation scenarios. Those criteria can be used to rationalize the transition between mild and severe Wear regimes and help define the notion of asperity.

  • emergence of self affine surfaces during Adhesive Wear
    Nature Communications, 2019
    Co-Authors: Enrico Milanese, Ramin Aghababaei, Tobias Brink, Jeanfrancois Molinari
    Abstract:

    Friction and Wear depend critically on surface roughness and its evolution with time. An accurate control of roughness is essential to the performance and durability of virtually all engineering applications. At geological scales, roughness along tectonic faults is intimately linked to stick-slip behaviour as experienced during earthquakes. While numerous experiments on natural, fractured, and frictional sliding surfaces have shown that roughness has self-affine fractal properties, much less is known about the mechanisms controlling the origins and the evolution of roughness. Here, by performing long-timescale molecular dynamics simulations and tracking the roughness evolution in time, we reveal that the emergence of self-affine surfaces is governed by the interplay between the ductile and brittle mechanisms of Adhesive Wear in three-body contact, and is independent of the initial state. Surface roughness evolution with time is key for tribological applications. Here, the authors demonstrate by numerical simulations the evolution of sliding surfaces into self-affine morphologies during Adhesive Wear due to the formation of a third body trapped at the interface.

  • Adhesive Wear mechanisms uncovered by atomistic simulations
    Friction, 2018
    Co-Authors: Jeanfrancois Molinari, Ramin Aghababaei, Tobias Brink, Lucas Frérot, Enrico Milanese
    Abstract:

    In this review, we discuss our recent advances in modeling Adhesive Wear mechanisms using coarse-grained atomistic simulations. In particular, we present how a model pair potential reveals the transition from ductile shearing of an asperity to the formation of a debris particle. This transition occurs at a critical junction size, which determines the particle size at its birth. Atomistic simulations also reveal that for nearby asperities, crack shielding mechanisms result in a Wear volume proportional to an effective area larger than the real contact area. As the density of microcontacts increases with load, we propose this crack shielding mechanism as a key to understand the transition from mild to severe Wear. We conclude with open questions and a road map to incorporate these findings in mesoscale continuum models. Because these mesoscale models allow an accurate statistical representation of rough surfaces, they provide a simple means to interpret classical phenomenological Wear models and Wear coefficients from physics-based principles.

Michael M. Khonsari - One of the best experts on this subject based on the ideXlab platform.

  • on the assessment of variable loading in Adhesive Wear
    Tribology International, 2019
    Co-Authors: Hossein Fereidouni, Saleh Akbarzadeh, Michael M. Khonsari
    Abstract:

    Abstract An experimental procedure for assessment of Adhesive Wear subjected to variable loading is presented. The applicability of the Miner's rule to variable loading and an experimental methodology for determining the Miner's rule constant is described. The results of extensive pin-on-disk tests subjected to various loading scenarios reveal that the cumulative power dissipation and entropy remain relatively constant and independent of the loading sequence. These findings offer a reliable approach for estimation of Wear when a component experiences variable loading.

  • on the integrated degradation coefficient for Adhesive Wear a thermodynamic approach
    Wear, 2018
    Co-Authors: K P Lijesh, Michael M. Khonsari, Satish V Kailas
    Abstract:

    Abstract Normal Adhesive Wear process in tribological components is characterized by a non-linear behavior during the transient running-in stage followed by a constant rate of steady-state Wear. Even though the running-in stage of Wear has an imperative significance in defining the component's long-term performance, its characteristics have been largely overlooked in the literature. In general, many of the available predictive models do not consider the contact temperature and the variation in the friction coefficient with time. The present work is an endeavor to propose a complete integrated Wear model using the principles of thermodynamics. In this regards, an integrated degradation coefficient is proposed which correlates the time-dependent Wear rates (at both running-in and steady-state stage), friction coefficient, and the contact temperature. The efficacy of the proposed degradation coefficient compared to established Wear coefficient is demonstrated by considering test results using a vertical pin-on-disk apparatus. Results reveal that the degradation coefficient provides a realistic measure of Wear during running period.

  • On the Applicability of Miner’s Rule to Adhesive Wear
    Tribology Letters, 2016
    Co-Authors: Saleh Akbarzadeh, Michael M. Khonsari
    Abstract:

    Miner’s rule is a simple relation typically used for assessment of the accumulation of damage and prediction of the remaining useful life of a component subjected to cyclic fatigue stress under variable loading sequence. In this paper, the validity of applying Miner’s rule to Adhesive Wear problem under variable, sequential loading is investigated. For this purpose, series of pin-on-disk experiments with different material combinations were performed to examine the behavior of Adhesive Wear subjected to variable loading sequence. The experimental results show that the loading sequence affects the weight loss. Applicability of Archard’s law for variable loading sequence is also investigated. It is shown that in the case of sequential loading, the Archard’s law is incapable of accurately predicting the weight loss. The dissipated power is calculated for all the experiments. It is shown that under the conditions tested for dry friction between steel on steel and steel on brass, the onset of failure occurs when the dissipated power reaches 0.15 and 0.06 W, respectively, regardless of the loading sequence.

  • on the applicability of miner s rule to Adhesive Wear
    Tribology Letters, 2016
    Co-Authors: Saleh Akbarzadeh, Michael M. Khonsari
    Abstract:

    Miner’s rule is a simple relation typically used for assessment of the accumulation of damage and prediction of the remaining useful life of a component subjected to cyclic fatigue stress under variable loading sequence. In this paper, the validity of applying Miner’s rule to Adhesive Wear problem under variable, sequential loading is investigated. For this purpose, series of pin-on-disk experiments with different material combinations were performed to examine the behavior of Adhesive Wear subjected to variable loading sequence. The experimental results show that the loading sequence affects the weight loss. Applicability of Archard’s law for variable loading sequence is also investigated. It is shown that in the case of sequential loading, the Archard’s law is incapable of accurately predicting the weight loss. The dissipated power is calculated for all the experiments. It is shown that under the conditions tested for dry friction between steel on steel and steel on brass, the onset of failure occurs when the dissipated power reaches 0.15 and 0.06 W, respectively, regardless of the loading sequence.